This invention relates to a braking mechanism using a toggle lever for a vehicle such as a truck or automobile.
Brakes for vehicles typically include some actuating mechanism that moves a cam, piston, or other device in an actuation direction for predetermined distance. This mechanism then moves a brake pad toward a surface to be slowed. This movement directly in the actuation direction of the brake pad requires that the actuation mechanism have sufficient force and ability to travel through a sufficient distance that it can apply supply sufficient movement to the brake pad and sufficient force.
There are limits on the available space, and it would be desirable to limit the amount of force required from the actuation mechanism. Thus, various braking mechanisms have been proposed which have force and distance movement multipliers. One proposed mechanism utilizes a toggle lever, including two arms connected at a central pivot point to a driving piston. This connection to the driving piston then results in the piston selectively being extended or retracted to drive the piston between retracted and extended positions. This arrangement is unduly complex, and the direct connection between the actuation mechanism and the two lever arms is undesirable. Moreover, the actuation movement is generally perpendicular to the resulting actuation direction movement of the brake pad, which is also undesirable.
In a disclosed embodiment of this invention, the braking mechanism comprises a toggle lever, a brake pad, and an incline. The toggle lever has two pivotally connected arms. An incline actuates the braking mechanism by forcing the extension of the toggle lever. During the extension, the two arms pivot to move the brake pad into contact. The incline for actuating the braking mechanism may be a wedge, a cam, or a curved surface moving in the direction of the brake pad. The incline is not fixed to the arms but is movable along a contact roller. Thus, there can be some adjustment due to the lack of direct connection. Moreover, it is preferred that the actuation direction is movable in the direction of the brake pad actuation movement.
One arm of the toggle lever is pivotally and operatively connected to a support for rotation about an axis. The two arms of the toggle lever are bent at an angle in relationship to each other when the lever is not actuated. The second arm of the toggle lever is operatively connected to a guide for translational movement in the direction of the brake pad. As the incline moves, it extends the toggle lever to an unbent position, pushing the brake pad closer to the surface to be slowed. A roller is used to improve the contact between the incline and toggle lever. The toggle lever multiplies the actuating force imparted by the wedge. By adjusting the width of the incline, the multiplying effect is also adjusted.
Another embodiment of the invention is the use of multiple toggle levers with a single incline. Multiple toggle levers operatively connect to a brake pad, permitting a single input from an incline to actuate all levers, greatly reducing the complexity of current braking mechanisms. The multiplying effect of all toggle levers is adjusted by the adjustment of the single incline. This single adjustment allows the braking mechanism to meet varying braking needs. No significant redesign of the braking mechanism is thereby required.